The present invention relates to portable communication devices which are provided with an input device using detection of vibration/inclination of the communication device for entering information into the portable device. Portable communication devices which are concerned are all type of handheld communication devices such as PDAs and mobile phones.
A great number of entering devices are known for these types of portable devices, such as keypads, touch screens used either with the finger, or with a specific stylus, 2D or 4D navigating means in form of one or more navigating keys, or even acoustic means for voice recognition. More recently, new entering devices based on the detection of movement of the portable device through detection of inclination of the portable device with respect to at least one axis, have been developed. These new entering devices include a tilt sensor among at least one of gyroscope, accelerometer, multi-axis gyroscope and multi-axis accelerometer.
Document US2005/0197145 discloses a mobile phone which allows a user to input a phone number in view of taking a call without any manipulation of the keypad, thanks to the use of vibration/inclination detection means. Each number, from 0-9, composing the phone number is deduced from the numbers of detected movements and inclinations according to a predetermined rule.
Document EP 1 591 873 discloses a method and apparatus for entering information into a portable electronic device with the help of a tilt sensor. According to this document, a tilt sensor is used to determine whether a change of inertia around at least one axis corresponds to a tapping of the input device, to identify a contacted region of the input device, and to perform at least one function based on the identity of the contacted region of the input device. The related functions are chosen among controlling a volume, scrolling through a menu or a list of items, selecting an item, and displaying characters or symbols. For entering a number or a character, the user needs to tap consecutively in several regions of the input device. The sequence of identified contacted zones will determine the corresponding character.
At last, a new mobile phone including a 3D accelerometer has come on the market. The accelerometer calculates and ascertains movement of the mobile phone in three dimensional space, and carries out commands according to those calculations. For example, a user will move the phone in the air in a gesture which draws number “3.” This motion is calculated by the accelerometer and figure “3” is displayed on the screen of the mobile.
Although this new way of entering commands, by motions of the mobile phone according to predetermined gestures, is very trendy, one possible drawback for the user will be to learn the correct gesture he will have to make for a given function, and also how he should handle his mobile phone when he starts any motion of the mobile phone. One reason is that the neutral position of the accelerometer, i.e. the reference position from which the calculations are made, is calibrated and fixed at the time of manufacturing the mobile phone, depending on the location and orientation of the accelerometer inside the housing. This means that, each time the user will have to use the accelerometer's functionalities, for instance for navigation purposes, he will have to first correctly position his mobile phone in order to be in correspondence with the neutral position of the accelerometer. For instance, if the neutral position of the accelerometer is defined for vertical position of the mobile phone, the user will have to start any gesture with handling first the mobile phone vertically.